1. Field of the Invention
This invention relates generally to apparatus and methods for dispensing liquids; and, more particularly, to apparatus adapted to depend from a bottle cap and into liquid within the bottle to permit repetitive dispensing of measured quantities of liquid.
2. Description of the Prior Art
Dispensing devices are frequently used in scientific laboratories where measured quantities of chemical reagents or the like must be transferred from storage bottles to test tubes or other small receptacles. When caustic, highly acidic, or toxic chemicals are involved, the user must typically disassemble the device in order to change the amount to be dispensed. For instance, in Echols U.S. Pat. No. 3,556,353, the user must remove the dispensing apparatus and cap from the bottle. Also, if the solution in the bottle is dark, one cannot read the scale on the delivery tube unless the plunger is pulled out.
Other prior art of interest, but having other or similar disadvantages and problems, are U.S. Pat. Nos. 3,653,556; 3,458,090; 3,452,901; 3,283,727; 3,191,807; 3,101,751; 2,805,798; and B497,853 (Feb. 17, 1976 under Second Trial Voluntary Protest Program).